In this resubmission, we request support for two graduate trainees selected each year, who have attained dissertator status in our predoctoral Columbia University Graduate Training Program in Microbiology and Immunology. Each trainee would be funded for two years. This PhD granting Program, led by our Director Dr. David Fidock and Co-Director Dr. Boris Reizis, provides predoctoral trainees with a unique opportunity to obtain individualized training across a broad spectrum of microbiology and immunology research. This research converges on themes of immune cell and tissue development and homeostasis, pathogen biology, mechanisms of DNA replication and repair, and microbial and immune cell proliferation. These cross-disciplinary interests are being pursued in a highly collaborative and interactive framework that links our 19 training faculty, who are all appointed to the Department of Microbiology & Immunology, led by our Chairman Dr. Sankar Ghosh. Our graduate program, built on many decades of successful graduate training, has proven that we can recruit and retain an outstanding cohort of training grant eligible (TGE) applicants. Trainees take courses in microbiology and immunology, biochemistry, molecular cell biology, genetics, quantitative biology, and responsible conduct in research, and are enrolled in workshops on scientific writing and grantsmanship. Students must also pass a qualifying examination that tests their ability to formulate and defend a hypothesis-driven project unrelated to their thesis research. Our programmatic framework includes a Steering Committee that regularly evaluates student and trainer performance, the curriculum, and new applicants; a process to identify the best trainees and mentor them successfully throughout their graduate studies; a mentoring plan for junior trainers, and an External Review Board with Program Directors who provide regular feedback to help optimize program effectiveness. Our Graduate Program has shown excellent recruitment and retention rates, along with an outstanding record of career outcomes for former predoctoral trainees, including underrepresented minorities or disadvantaged students. 95% of our former trainees in the past decade have continued in science or medicine and 15% have already achieved tenure-track or non tenure-track faculty positions. Our increased emphasis on recruitment of underrepresented minorities includes a new agreement with the University of Puerto Rico, which has a large student body of TGE applicants, and extensive outreach initiatives. We also benefit from very strong institutional support provided by the Dean of our medical school and our Office of Graduate Affairs, including financial support that allows our training grant to support selected trainees once they have successfully completed their coursework and qualifying examination and are engaged in full-time research. We are confident that our dynamic, rigorous and scientifically innovative training program will mold future academic leaders in microbiology and immunology research who will have acquired the skills to be able to tackle critical topics in infectious diseases and immune regulation.